Useful Links

We have found the following links to be interesting and useful in our research developing microsensors for in-situ chemical detection and characterization. If you have a site that you would like to have included on this page, please send the URL and brief description to Cliff Ho.

In addition, please visit the following web site for more information on other microsystem technologies at Sandia National Laboratories: www.sandia.gov/mstc

Chromatography and Spectrometry Sensors

Chromatography is a method for the separation and analysis of complex mixtures of volatile organic and inorganic compounds. A chromatograph is essentially a highly efficient apparatus for separating a complex mixture into individual components. As the mixture is separated by the column, a detector positioned at the end of the column quantifies the concentrations of the individual components.

Spectrometry can be considered a sub-class of chromatography. A gaseous sample is injected into the spectrometer and ionized by a radioactive source, resulting in positive and negative charged species. These species are accelerated over a short distance and the time-of-flight is determined.

  • Agilent Technologies offers a full line of laboratory and field Gas Chromatographs.
  • Femtoscan has developed a hand portable Gas Chromatograph/Ion Mobility Spectrometer (GC/IMS) instrument.
  • INFICON HAPSITE Chemical Identification System is a field-portable Gas Chromatograph/Mass Spectrometer (GC/MS) for on-site analysis of VOCs.
  • Bruker Daltonics, Inc. has developed a lightweight, rugged GC/MS system for analysis of air, water, and soil.
  • Process Analyzers produces a field portable instrument which is able to analyze liquids, soilds, and gasses.
  • Sandia National Laboratories has developed the Micro-Chem-Lab on a chip (uChemLab) that is a miniaturized GC-type device.
  • Bruker Daltonics, Inc. has developed a hand-held chemical agent detector based on IMS.
  • DLK Spectro has produced an IMS with a gas-chromatic cell for gas analysis.

Electrochemical Sensors

Electrochemical sensors can be categorized into three groups: (1) potentiometric (measurement of voltage); (2) amperometric (measurement of current); and (3) conductometric (measurement of conductivity). In general, electrochemical sensors interact with the contaminant of interest. This produces changes in its electrical properties that are measured and related to concentration.

  • Cyrano Sciences (TM) developed the Cyranose 320 which mimics smelling and contains an array of 32 sensors.
  • Adsistor Technology (TM) developed and patented a chemiresistor for vapor detection of gasoline spills and leaks in the subsurface.
  • GasTech (TM) has a portable soil vapor monitor that uses a catalytic bead sensor for detection of hydrocarbon gases.
  • Figaro has develop metal-oxide semiconductor sensors for detection of solvent vapors.
  • City Technology is a leading manufacturer of gas sensors using catalytic bead, semiconductor, and infrared technologies.
  • Delphian Corporation manufactures several potentiometric devices for sensing toxic gases and oxygen.
  • National Center for Environmental Research, an office of the EPA, uses chemiresistors for air quality monitoring.
  • The Jet Propulsion Laboratory has developed a selective silicon carbide material for use hydrocarbon sensing.

Mass Sensors

Surface Acoustic Wave Sensors (SAWS) are small miniature sensors used to detect VOCs. A SAW device consists of an input transducer, a chemical adsorbant film, and an output transducer on a piezoelectric substrate. The input transducer launches an acoustic wave which travels through the chemical film and is detected by the output transducer. The velocity and attenuation of the signal are sensitive to the viscoelasticity as well as the mass of the thin film which can allow for the identification of the contaminant. A signal pattern recognition system that uses a clustering technique is needed to identify various chemicals.

  • Sandia National Laboratories has developed and tested a six-array Surface Acoustic Wave (SAW) device able to identify 14 different individual organic compounds over a wide range of concentrations with 98 percent accuracy. An integrated GaAs SAW sensor device has been integrated with a microprocessor on a single 5mm x 5mm chip. A hand-held Portable Acoustic Wave Sensor (PAWS) system using the SAW sensor that can be used down-hold for monitoring. High temperature SAW devices are also being developed for monitoring in temperatures as high as 525 degrees C.
  • PNNL has developed a portable sensor to detect real-time Chemical Weapons dispersal in the field using a portable SAW sensor.

Optical Sensors

Fiber optic sensors are a class of sensors that use optical fibers to detect chemical contaminants. Light is generated by a light source and is sent through an optical fiber. The light then returns through the optical fiber and is captured by a photo detector. Three general classes of fiber optic sensors include: (1) passive spectroscopic; (2) chemically interacting thin film attached to the tip of the fiber; and (3) injection of a reagent near the sensor.

  • PNNL S&E – Remote Chemical Vapor Characterization using infrared spectroscopy technology.
  • The Laser Lab in Germany has developed an optical sensor for analyzing polycyclic aromatic hydrocarbons (PAHs) and monoaromatics like benzene, tolouene, xylene, and ethylbenzene. Scroll down page to abstract
  • Ion Optics, Inc. offers a MEMS infrared gas sensor.
  • Georgia Institute of Technology has developed an environmental monitoring system based on integrated optic sensors.
  • Burge Environmental offers the Optrode Detection System for TCE.

Biological Sensors

Biological sensors rely on biologically produced enzymes or biocatalysts to detect the presence of a contaminant of interest.

  • INEEL led research to use molecular engineering and genomics for the development of environmental biosensors using robust biocatalysts

Characterization Technologies

Sandia National Laboratories Visual Empirical Region of Influence (VERI) Algorithm. Presents a new, nonparametric pattern recognition (PR) method based on the visual empirical region of influence (VERI) clustering technique. Innovative Technology Summary Report (April, 1996) describes the use of a cone penetrometer to provide cost-effective, real-time data for the use in characterization of the subsurface. The cone penetrometer uses sensors to measure cone tip pressure and sleeve friction. Other sensors available include two-axis inclinometers, acoustic cone (for identificaiton of soil type), temperature, pH, radioactivity (gamma), and geophones for measurement of pressure (P) and shear (S) waves (surface to borehole seismic measurements). EIC Laboratories, Inc. has developed two optical sensors for the cone penetrometer used for the detection of DNAPLs. The U.S. Army Environmental Center has developed the Site Characterization and Analysis Penetrometer System (SCAPS) which uses an in situ HydroSparge Volatile Organic Compound (VOC) Sensor incorporated into a cone penetrometer truck.

Data Collection and Telemetry

Aquasat has a satellite-based remote telemetry system (EcoPod) that can been integrated with sensors and systems for detecting contaminants in water resources. NetAcquire products combine three key technologies: intelligent real-time data acquisition, signal processing, and high-speed networking. Voss Scientific offers a PC-Based Telemetry Server Suite that utilizes satellite technology to transfer data. ADCON Telemetry offers systems for permanent data collection, reliable data transfer, and user-friendly data visualization on the PC.

Other

  • SENSORS Online Journal
  • Sensors Web Portal with monthly updates on sensors, tools, patents, etc.
  • Sensors Magazine Online
  • INEEL Grand Challenge for Subsurface Characterization. Describes need for remote sensing of more parameters, localized sensing of more parameters, comprehensive point measurements, and measurement integration.
  • Eksigent combines micropumping, microfluidics, and microfabrication for use in creating new devices for use in the life sciences, MEMS, and microelectronics industries.
  • Adsistor Technology, Inc. offers gas and chemical vapor sensors.
  • EnviroEquip offer a variety of instruments for environmental monitoring.
  • Patent information for a hydrocarbon vapor sensing unit (US6102085). Many reference links to other sensors on this page.
  • ThermoGasTech has a Portable Soil Vapor Monitor for hydrocarbons available.
  • Ronan Engineering Company manufactures industrial process instrumentation such as annunciators, temperature transmitters, alarm monitors, leak detection monitors, non-contact level/flow/density, IS barriers, I/P transducers, graphic displays, vibration monitors, and calibrators.
  • INEEL Grand Challenge for Subsurface Characterization. Describes need for remote sensing of more parameters, localized sensing of more parameters, comprehensive point measurements, and measurement integration.
  • Eksigent combines micropumping, microfluidics, and microfabrication for use in creating new devices for use in the life sciences, MEMS, and microelectronics industries.
  • Adsistor Technology, Inc. offers gas and chemical vapor sensors.
  • EnviroEquip offer a variety of instruments for environmental monitoring.
  • Patent information for a hydrocarbon vapor sensing unit (US6102085). Many reference links to other sensors on this page.
  • ThermoGasTech has a Portable Soil Vapor Monitor for hydrocarbons available.
  • Ronan Engineering Company manufactures industrial process instrumentation such as annunciators, temperature transmitters, alarm monitors, leak detection monitors, non-contact level/flow/density, IS barriers, I/P transducers, graphic displays, vibration monitors, and calibrators.
  • PetroVend offers liquid and vapor hydrocarbon sensors for monitoring wells.
  • Delphian Corporation offers gas monitoring and vapor leak detection systems.
  • American Gas & Chemical Co Ltd offers gas monitoring and vapor leak detection systems.
  • RAE Systems offers various gas detection capabilities.
  • Savannah River website offering ER technology descriptions.
  • VaporTec offers state-of-the-art passive soil gas sampling services.
  • Photonics Technology News Chemical Sensor Offers Sensitive Real-Time Solution.
  • Sentex Systems, Inc. offers solutions for on-line, on-site VOC monitoring in air, water, and soil.